You can download pre-recorded audio files of the right type from
This Page, when you have chosen the actual voice you want make sure you select either the Consolidated or Speed Zoned download as either of these contain the redlight warning you want. Liz Whitaker is the one I use all the time if you want a matching navigation voice recorded by Liz PM me your e-mail address and I can send it over.
With the download unzipped you will hve a number of ogg files, you need to rename the redlight warning file name to exactly match your redlight POI file.
Put the renamed ogg file into your map folder along with all the POI files and start up the TomTom.
Go to Change Preferences/ Manage POI/ Warn When Near POI and find your redlight camera, if its already been configured select it again and answer NO to the question about removing the warning, if you have never had this configured select the RedLight camera from the list.
Enter a distance, select the option "Sound effect" the device will then show a screen with the mesage "Is this the sound you want to select" - it won't play anything for you to hear but press YES, (if you press No the device will lock up requiring a prod with a paperclip in the reset hole). If you don't get the Yes/ No option and the device still offers all the normal built in sounds your ogg file is probably incorrectly named. Set the Warn only if POI is on route as per your own preference.
To test this is working either go out for a run in the car or use the AtoB Advance Planning and create a route that goes past a camera, put the unit into demo mode and sit back watch/ listen what happens - Mike